The authorities fear any sign that the militant spirit of the Yellow Vests might make its way into the working class. That is why, seeing merged columns of the two groups in Paris, the police attacked not just the Yellow Vests but also the official CGT union federation.

Philippe Martinez, leader of the CGT, was tear-gassed. He later condemned the fact that “police charged the CGT”. He added that “grenade shots even reached our van”.

In a British context it would be as if the cops had assaulted Frances O’Grady of the TUC.

Another union block, Solidaries, was also assaulted by police, as were a group of Sud-Rail militants.

The Alliance police union retorted that “Philippe Martinez is part of the collateral damage” of dealing with the Yellow Vests.

Around 300,000 people took part in marches across France. The official count grudgingly crept up during the day as the media began to report big numbers.

The numbers were “twice as many as 1 May 2018” according to the BFMTV news channel and “the strongest mobilisation for seven years" according to Ouest-France news. Around 60,000 people marched in Paris.

The police had been encouraged by statements made by Macon in the run-up to May Day. He called for “an extremely firm stance” against any violence, and major areas of the capital were in lockdown.

Bernard, A CGT union rep on the railways, told Socialist Worker, “I am used to being attacked as a Yellow Vest by the police on our weekly demonstrations. But it was a surprise when they carried out similar tactics when I was in my union red vest.

“They were shooting water cannons at our union giant balloons. But at last I felt the slogan Tous Ensemble (All Together) meant something. We were together in the firing line, together in at least many of our demands.”

Interior minister Christophe Castaner made much of his claim that protesters had “attacked the Hospital of the Pitie-Salpetriere”.

But an eyewitness reported, “I saw these protesters at the entrance of the hospital who wanted to take refuge from a column of CRS riot police who had arrived by the top of the boulevard. Then the police commissioner spotted these people at the entrance and ordered the police after them.”

A video tweeted by the writer and filmmaker David Dufresne showed the police then battering people.

By the end of the day, the ministry of the interior said there had been 330 arrests and more than 15,300 “preventative checks”. The Paris prosecutor’s office, which had doubled its number of magistrates for the day, announced 315 people in police custody.

Macron has combined savage repression and occasional retreats in an effort to break the Yellow Vest revolt.

In a major speech last week he combined meagre retreats on tax and pensions with demands for people to work more hours each week and complaints that “France works a lot less than its neighbours”.

Neither concessions nor brutality have stopped the protests. This Saturday will be the 25th successive week of mobilisations.